The present invention relates to an ultrasound imaging method and apparatus which produce ultrasound images, and in particular, to an ultrasound imaging method and apparatus which produce intracranial ultrasound images.
Ultrasound imaging which produces ultrasound images by transmitting an imaging ultrasonic beam from an ultrasound probe toward a subject and receiving the ultrasonic echo reflected by the subject is known. In recent years, ultrasound imaging has been applied to intracranial observation. For example, intracranial ultrasound images have been produced by transmitting an imaging ultrasonic beam toward a subject inside a cranium from a thin place on the cranium such as the temple.
In this type of intracranial ultrasound imaging, multiple echoes occur, wherein part of the imaging ultrasonic beam transmitted inside the cranium is repeatedly reflected by the inner surface of the cranium and so forth. Multiple echoes of the imaging ultrasonic beam result in noise in the produced ultrasound image, and also have the risk of affecting brain tissue.
Thus, in JP 2007-117165 A, for example, a technique is proposed whereby, in multiple echoes occurring between the surface of the ultrasound probe and inside the body, noise in the ultrasound image is reduced by cancelling out echoes reflected by the ultrasound probe.
However, even if the echo reflected by the surface of the ultrasound probe is cancelled out, multiple echoes of the ultrasonic echo occurring on the inner surface of the cranium still exist, and there is risk that the remaining ultrasonic echoes affect brain tissue.